OAKLAND -- Trading away big league talent is a common occurrence in the small-market confines of Oakland. So too, though, is the acquisition of excellent young players.

The A's infused an abundance of talent during the offseason, with the returns from the trades of All-Stars Gio Gonzalez, Trevor Cahill and Andrew Bailey resulting in a boon for the farm system.

Not only did they bring in a lot of new players, but many of them were already at the upper levels of the Minors, and the A's are reaping the benefits much sooner than anticipated. The likes of Jarrod Parker, Tommy Milone and Derek Norris are already contributing in big ways at the Major League level.

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There are still plenty of players to keep an eye on at the Minor League level, where the A's added five new names to their Top 20 prospect list since the beginning of the season.

More on these players, as well as the others circulating around them:

Graduated

The A's celebrated five graduations this season, with Parker, Milone, Chris Carter, A.J. Griffin and Norris all acquiring the necessary Major League service time to break free from the list. Life outside of the list has treated each well, as hurlers Parker, Milone and Griffin have all contributed to one of the league's best pitching staffs, their success coming much sooner than anticipated. Norris, meanwhile, took over everyday catching duties for the A's when Kurt Suzuki was traded, and Carter finally appears to have found comfort in the Majors, with double-digit home runs after three prior disappointing stints.

Dropped off

The A's are the only team without a player who fell off the preseason Top 20 list.

New faces

The A's not only welcomed in five new faces to the team's Top 20 list, but they saw four break the Top 10. Righty Dan Straily entered the list at No. 2, following a dominant 2012 campaign that saw him compile 190 strikeouts in 152 innings between Double-A and Triple-A. The club's first-round Draft pick, shortstop Addison Russell, made his debut on the list right behind Straily at the No. 3 spot. Russell was quickly promoted from rookie ball to Low A to High A in a matter of months after being drafted, compiling a combined .369 average with seven home runs, 45 RBIs and 16 stolen bases in 55 games.

Miles Head, acquired in the Andrew Bailey trade, is ranked as the club's ninth-best prospect. Head split his time between Class A Stockton and Double-A Midland this season, batting .333 with 23 home runs and 84 RBIs in 124 games. The third baseman was joined on the list by No. 10 prospect Daniel Robertson, another first-round Draft pick (34th overall) this year. While splitting time at third base and shortstop, Robertson posted a .241 average in his brief time on the field, spanning 55 games between the Arizona Rookie League and Low A Vermont.

Familiar name Michael Taylor, meanwhile, did not make the preseason Top 20 list, but he found his way to the new list at No. 14. Long considered a top prospect, Taylor has yet to enjoy a long stay with the big league club. He hit .287 with 12 home runs and 67 RBIs in 120 games for Triple-A Sacramento this year.

athletics' top prospects

Lefty Ian Krol, a seventh-round pick by the A's in the 2007 Draft, was victim to the biggest drop on the list, moving from No. 10 to No. 19, despite earning a promotion to Midland late in the year. He appeared in eight games as a reliever for the RockHounds, compiling a 5.06 ERA. This came after he tallied a 5.21 mark in 21 games (15 starts) with Class A Stockton.

Shortstop Yordy Cabrera, taken by the A's in the second round of the 2010 Draft, has struggled in his three seasons of professional ball, and he, too, was dropped on the list. After batting just .232 in an injury-plagued 2012 season for Class A Stockton, Cabrera went from No. 8 to No. 16.

Making a notable jump in the list was catcher Max Stassi, who moves from No. 19 to No. 12. He, too, endured a shorter season than most because of injury, but during his time at the plate he hit .268 with 15 home runs and 45 RBIs in 84 games in his second season with Stockton.

Top 100 representation

The A's have four representatives on MLB.com's list of the Top 100 prospects in baseball. Outfielder Michael Choice sits at No. 71 -- 12 spots below his preseason No. 59 ranking -- while Straily is next at 81. Russell is at No. 97, while A.J. Cole, acquired in the Gio Gonzalez trade, makes the cut at No. 99.

With several of its preseason-ranked top prospects making major strides sooner than expected, the A's system's stock as a whole fell in the eyes of MLB.com's observers, dropping from the 13th organization in baseball to No. 24. But the Major League club was the beneficiary.

Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.